New Delhi: During the 26th meeting of the General Conference on Weights and Measures (CGPM), metrologists and policy-makers from around the world have voted for the redefinition of 130 years old “Le grand K – the SI unit of kg” in terms of the fundamental Planck’s constant(h) and the ampere, the Kelvin and the mole. The meeting which was held from November 13 to 16 at Palais des Congrés, Versailles, France comprised of 60 countries which includes India and 42 Associate Members. Also Read - Confined By Coronavirus, French Man Runs 42.2 Km Marathon on 7-Metre Balcony During Lockdown

The new definitions of the International System of Units (SI) will come into force on May 20, 2019. The responsibility to define the SI units lies with the International Bureau of Weights and Measures (BIPM), the main executive body of CGPM. The SI units were revised after many years of intensive scientific cooperation between the National Metrology Institutes (The national Physical Laboratory for India) and the BIPM. Also Read - 'Efforts Made to Restore Normalcy But Curbs Should be Lifted,' Says French Envoy After Visiting Kashmir



The representatives of India for the meeting were Avinash K. Srivastava, Secretary, Department of Consumer Affairs, Government of India, D K Aswal, Director, National Physical Laboratory(NPL), New Delhi and T D Senguttuvan, Head Planning, Monitoring & Evaluation, NPL. Also Read - France Reports First Coronavirus Casualty, Life of 80-year-old Chinese Tourist Claimed by Virus

The seven base units namely, second, metre, kilogram, ampere, Kelvin, mole and candela will now be measured based on the fundamental constants on nature rather than being linked to artefacts. The responsibility to disseminate the SI units for the welfare of society and industries in India lies with  Legal Metrology, Department of Consumer Affairs, Government of India.



The definition of “Le Grand K” or kilogram which is currently set by a 143-year-old platinum alloy cylinder in BIPM in Paris will be changed to the physical constant Plank. Similarly, the definition of the metre has been changed to the speed of light.

According to a press release, the redefinition in the SI units will ensure uniformity worldwide and easy accessibility for “for all people, for all time” which includes international trade, high- technology manufacturing, human health and safety, protection of the environment, global climate studies and the basic science.

The day when the SI units will be refined, on May 20, 2019, is also known as the World Metrology Day.